Camarig, Jemark P.; Miroy, Lionel Ben Perseus C.; Yang, Katrina Marie T. (January 2003)
Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHS WVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines
ABSTRACT
The community structure of two mangrove communities in Ibajay, Aklan- a climax community in Bugtong-Bato (Site 1) and a disturbed community in Naisud (Site 2) was compared in terms of a) basal area, b) species diversity, c) relative frequency, d) relative dominance, and density of species. The number of trees, saplings, and seedlings per species were counted in two 100m² quadrants. The girth of mangrove trees at breast height (DBH) in these quadrants was also measured to compute for basal area as estimate of aboveground biomass of the plants. Physico- chemical conditions of the study sites were described in terms of: a) soil salinity, b) soil pH, temperature, and d) soil particle size composition.
Eight true mangrove species were observed in the climax mangrove community, namely: Avicennia rumphiana, Xylocarpus granatum, Ceriops decandra, Bruguiera cylindrica, Avicennia officinalis, Acanthus ilicifolius, Heritiera littoralis and Nypa fruticans. Six mangrove species were found in the disturbed mangrove site, namely: Ceriops decandra, Avicennia rumphiana, Sonneratia alba, Avicennia marina and Nypa fruticans. The species diversity of climax mangrove area was slightly higher (H= 0.7768) compared with that of the disturbed mangrove area (H= 0.6871). The total number of trees, saplings and seedlings (9/200 m², 7/200 m² and 55/200 m², respectively) were lower in the climax community than in the disturbed community (135/200 m², 87/200 m² and 411/200 m², respectively). Total basal area was higher in Site 1 (6823.884 cm²) compared with Site 2 (1074.408 cm²). The number of trees, saplings and seedlings, as well as the relative density and relative dominance was highest for Avicennia rumphiana in the Site 1. In Site 2, the number of trees and seedlings as well as the relative density was highest for Ceriops decandra while the highest dominance was that of Avicennia rumphiana.
Physico-chemical conditions in the sites did not vary widely. Soil temperature ranged from 24.7-32.0 °C, soil pH from 5.6-6.2 units, and soil salinity from 0-11 ppt. Soll was 638-66% coarse sand, 27%-31% fine sand and 5%-9% silt and clay.